1. Field of the Invention
The present invention relates to an apparatus for performing binary encoding or quantizing of image signals.
2. Description of the Prior Art
One conventional system for binary encoding of image signals is known in which image signals read from an original are binary encoded in accordance with a fixed threshold level. However, with this system, it is frequently impossible to separate a background portion and a data portion of an original.
Another conventional system is also known in which an original is scanned preliminarily to statistically determine a threshold level and image signals obtained in actual scanning are processed in accordance with the determined threshold level. However, this system requires scanning of a single original twice, resulting in time-consuming operations.
When the threshold level is statistically calculated and determined, if the threshold level is determined for performing binary encoding of all types of image signals which may be encountered, some portions of originals may be skipped and cannot be processed.